Barry White said it all so well a while ago and I have kept it on file (thanks
Barry):

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Thanet had ten ancient ecclesiastical parishes :
Acol, Birchington, Minster in Thanet, Monkton,
Sarre, St John in Thanet, St Lawrence in Thanet,
St Nicholas at Wade, St Peter in Thanet, Stonar
'ancient' meaning in existence before the 16th century. Spelling & notations vary ~
St Lawrence was frequently written with a 'u' rather than 'w', and (providing the
context is known) it is usual to drop the 'in Thanet', but care is needed to avoid
confusion with (say) Minster in Sheppey or St Lawrence in Canterbury.

Three of these parishes have not had a parish church since the 16th century or
earlier :
Acol, Sarre, Stonar
The others have parish churches dedicated as follows :
Birchington : All Saints
Minister in Thanet : St Mary the Virgin
Monkton : St Mary Magdalene
St John in Thanet : St John the Baptist
St Lawrence in Thanet : St Lawrence the Martyr
St Nicholas at Wade : St Nicholas
St Peter in Thanet : St Peter the Apostle

For four parishes, the associated town has the same name :
Birchington, Minster, Monkton, St Nicholas at Wade
For the three without churches, there is no associated town as such, but their
inhabitants generally attended church in one of the following :
Birchington, Monkton, Sandwich (Stonar only)
For the remainder, the associated town has a different name :
St John in Thanet : Margate
St Lawrence in Thanet : Ramsgate
St Peter in Thanet : Broadstairs
Note that Sandwich, mentioned above, is not in Thanet.

Originally, all of the above towns were 'villes' within the ancient parish. In the
case of the last three at least, the roles have reversed, and as the villes became
towns so the names of the parishes came to designate areas within them.

Matters get more complicated into the 19th century, and after c1825 you will
encounter more churches, parishes & places (mostly in Margate, Ramsgate &
Broadstairs), and a major new town (Westgate) built after the 1860s. For a list of
Thanet's churches & chapels see :http://users.iclway.co.uk/barrywhite/
This site also provides a 1891 census places index ~ although a census finding aid,
also it can be used to identify the parishes for many of Thanet's places in the late
19th & early 20th century.